Electrical control means for change-speed gearing



Nov. 10, 1953 ELECTRICAL CONTROL MEANS FOR CHANGE-SPEED GEARING FiledMay 51. 1951 I A. A. MILLER 2,658,408

4 Sheets-Sheet l m wk In v (En-bOD Nov. 10, 1953 MILLER 2,658,408

ELECTRICAL CONTROL MEANS FOR CHANGE-SPEED GEARING Filed May 51, 1951 4Sheets-Sheet 2 ezvboz izwijyzzaz z Nov. 10, 1953 A. A. MlLLER 2,658,408

ELECTRICAL CONTROL MEANS FOR CHANGE-SPEED GEARING Filed May 31, 1951 I 4Sheets-Sheet 5 ,zliwezvtol Lien Nov. 10, 1953 A. A. MILLER 2,658,408

ELECTRICAL CONTROL MEANS FOR CHANGE-SPEED GEARING Filed May 51, 1951 4Sheets-Sheet 4 Patented Nov. id, i953 UNIT.

ELECTRICAL CQNERQL MEANS FOR CHANGE-SPEED GEARING Application May 31,1951, Serial No. 229,114

@laims priority, application Great Britain June 5, 1950 21 Claims.

This invention relates to electrical control means for change speedgearing of the kind comprising electrical circuits controlled by contactmembers or switches and means controlled or actuated by said circuitsfor automatically effecting the engagement of either a higher or a lowergear in accordance with the closing or open ng of one or other of saidcircuits. She invention may be applied with particular advantage toarrangements of the above kind including electrical contact membersmovable relatively in two directions, movement in one direction being111 accordance with the speed of a part of the tra mission and movementin another tion being in accordance with the fuel sup ply or throttleopening or" an internal combustion prime mover, as described for examplein British patent specification No. 457,269. invention may be applied.to gearing provided with any convenient means for eiiecting the changesin gear ratio, such for example as fluid actuated devices controlled byelectro-magnetically operated valves, and such devices may be employedto actuate the brakes of epicyclic gears affording the required ratios,although the mvention is not restricted to the use of such actuatingmeans.

It is an object of the invention to provide control means of the abovekind which can addition be manually controlled by selecting and engagingany desired gear irrespective of the particular gear engaged.

A further object of the invention is to enable control means of theabove kind having automatic control in accordance with speed and fuelsupply or throttle opening conditions of a prime mover to be manuallyinstead of automatically controlled when required so that a desired gearratio can be maintained irrespective of the aforesaid conditions, and toprovide convenient and easily operable means for achieving this result.A further object is to provide alternative manual and automatic controlmeans which may be exchanged with saiety at any time while thetransmission is in motion without risk of over-speeding the prime mover,such as might occur 1:" on changing from manual to automatic control aninappropriate change to lower gear were produced. A further object is toprovide an proved construction of manually operable switch for the abovepurposes. A further object is to provide an improved construction ofgovernor actuated electrical contact members.

The invention consists in electrical control means for change speedgearing comprising elecn t t adam -1 e-cg afi a; E Ai this i hai it (Cl.Wi -472) trical circuits controlled by contact members or switches,means controlled or actuated by said circuits for automaticallyeffecting the engagernent of either a higher or a lower gear inaccor-dance with the closing or opening of one or other of saidcircuits, and manually operable selection switch means for interruptingsaid circuits and for selectively closing other circuits includingelectrical means for controlling engagement of diiierent gear ratios,the arrangement being such that gear changing is effected either by thefirst said circuits or by the second said circuits according to theposition of the selection switch means.

The invention also consists in electrical control means for change speedgearing comprising electrical contact members movable relatively in twodirections, movement in one direction being in accordance with the speedof a prime mover or transmission part and movement in another directionbeing in accordance with the fuel supply or throttle opening of theprime mover, electrical circuits controlled by said contact members,means controlled by said circuits for automatically selecting andengaging different gear ratios in accordance with speed and fuel supplyor throttle opening conditions, and manually operable selection switchmeans for interrupting said circuits and-for selectively closing othercircuits including electrical means for controlling engagement of thedifierent gear ratios, the arrangement being such that gear changing iseither automatic or manually controllable according to the position ofsaid selection switch means.

The invention also comprises an arrangement according to either of thetwo preceding paragraphs in which the first mentioned contact members orswitches control the circuits of relays for eifecting operation of aselection switch, through ratchet or other means in one or otherdirection to close circuits for actuating different gear ratioengagement means, said relays being provided with time delay means, forexample a shunt connected condenser or an additional short-circuitedwinding or induction sleeve so that they cannot operate successivelywithin a predetermined peiod. lj'he engagement of the selected gears iseffected through the medium of electro-magnetic devices which arepreferably energised by relays, thereby reducing the current to becarried by the contacts of the selection switch. These relays are alsopreferably provided with time delay means.

According to a further feature of the invention, the manually operableselection switch is provided with a contact or contacts arranged to beautomatically gaged each time the switch is operated to change the gearratio, such engagement causing the closing of a circuit associated withthe automatic selection switch to ensure the positioning of the latterin an intermediate gear position and thereby obviate inappropriate gearchanges.

A current economising resistance may be included in the circuits of thegear engaging control devices, and means may be associated with theautomatic and manual control circuits for short-circuiting saidresistance at each gear changing operation. Thus in a preferredarrangement, means is provided for locking the operating handle of themanually operable selection switch in the selected positions, and themotion required to unlock the handle causes contact means to becomeoperative and to effect the closing of a circuit or circuits when thehandle is moved to another position and thereby short-circuit theresistance.

In the accompanying drawings,

Figure 1 is a diagram showing the connections of an electrical controlmeans for change speed gearing arranged in accordance with theinvention;

Figure 2 is a sectional elevation, with certain details omitted, of thebrake actuating and control mechanism for an epicyclic gear box for usein conjunction with control means according to the invention;

Figure 3 is a sectional elevation of a manual selection switchconstructed and arranged in ac cordance withthe invention;

Figure 4 is an end elevation of the selection switch as viewed in thedirection of the arrow A in Figure 3;

Figure 5 is a sectional elevation, taken on the line 5-5 of Figure 6, ofa governor and throttle control mechanism constructed and arranged inaccordance with the invention;

Figure 6 is a cross section of the mechanism of Figure 5;

Figure '7 is a section taken on the line 1-7 of Figure 6 Figure 8 is adiagram showing the connections of a modified form of electrical controlmeans.

In carrying the invention into efiect according to one convenient mode,the connections for a control arrangement intended to be applied to anepicyclic gear box aifording four forward gear ratios and reverse isshown in Figure 1. A governor actuated electrical contact arrangement isprovided comprising a movable contact member I connected to a speedgovernor and displaceable in relation to a pair of shaped contactsurfaces 2 and 3 which are themselves movable in a different directionin accordance with the fuel supply and throttle opening as described inBritish patent specification No. 457,269. The contact surface 2 isconnected to the coil 4 of a change-up relay having a movable armature 5controlling contacts 6 and 'I. The contact surface 3 is connected to thecoil 8 of a change-down relay having movable armatures 9 and Id. Thearmature 9 controls contacts H and I2 and the armature Ill controls backcontacts 13 and I l. The contacts 6 and l of the change-up relay controlthe circuit of an electromagnet [5 having an armature It for actuating aratchet'pawl ll loaded by a spring IS. The contacts H and I2 of thechange-down relay control the circuit of an electromagnet l9 having anarmature for actuat- 4 ing a ratchet pawl 2| loaded by a spring 22. Theratchet pawls I1 and 2| are arranged so that when operated they engage aratchet wheel 23 to which is connected the contact arm of an automaticselection switch. This arm is not shown in Figure 1, but it carries fourcontact strips 24, 25, 26 and 27. Operation of the ratchets causes stepby step displacement of the ratchet wheel 23 in one or other directionaccording to which ratchet is operated. The movable contact member l ofthe speed governor is connected through a resistance 28 and pairs ofcontacts 29 and 30, which are broken when the ratchets are operating, toone of a pair of contacts on a manual selection switch to be describedhereinafter, which contacts are bridged when the said switch is inposition for automatic operation, and the second of said contacts isconnected to the positive side of the electrical supply which mayconveniently comprise a battery. Thus the aforesaid relays can beenergised through the governor actuated contacts I and 2 or I and 3 onlywhen the manual selection switch occupies an appropriate position.

The relay coil 4 is connected to a series of contacts 3| on theautomatic selection switch which can be connected by the switch strip 24to contacts 32 which are connected to the negative side of the supplybattery 33. Similarly the relay coil 8 is connected to a series ofcontacts 34 which can also be connected by the switch contact strip 24to the negative side of the supply. The switch arm has four positionscorresponding to first, second, third and fourth speeds, the reversebeing obtained by manual control only. In Figure 1 the lowest radialline of contacts occupied by the switch contact strips 24, 25, 26 and 2?corresponds to first speed, the line of contacts above it to secondspeed, the line above that to third speed and the upper line to 'fourthspeed. It will be seen that the series of contacts Si, 32 and 34 are soarranged that in each end or limit position of the switch arm thecircuit of one of the relay coils 4 or 8 is interrupted. The arrangementis such that if the automatic selection switch is in a positioncorresponding to second speed for example, and the engine speed rises toa predetermined value, the governor actuated contact member I will moveto close the circuit of the change-up relay 4 which causes actuation ofthe magnet 15 and ratchet H to move the automatic selection switch armto the next position corresponding to third speed. If, however, theswitch arm is already in fourth speed position, there is no contact ofthe series 3| connected to the relay coil 4 and hence the relay cannotbeenergised. The same considerations apply when changing down, since thelowest contact of the series 34 has no connection with the relay coil 8.The relay coils 4 and 8 are shunted by condensers 35 and 36 so that atime lag of a few seconds is introduced which prevents successiveoperations within a shorter time interval.

The contact strip 25 of the ratchet switch arm controls series ofcontacts 31 and 38. The contacts 31 are connected through the manualselection switch to the positive side of the battery 33, this connectionbeing made only when the said switch is in position for automaticoperation as will be described hereinafter. The contacts of series 38are connected respectively to the coils 39, 40 and Al of three valvecontrolling relays corresponding to first, second and third speeds.These ralays are preferably equipped with induction sleeves to provide atime delay in their operation. The relay coil 39 can actuate a movablecontact 42 to make with a fixed contact l? connected to an electromagnetMl to bring in the first speed gear as hereinafter described. Themovable contact 42 also has a back contact 35 which is connected to theback contact i l of the change-down relay 8. The movable contact 46 ofthe relay M3 is arranged to make with a fixed contact All connected toan electromagnet i8 for bringing in the second speed gear. The movablecontact 46 also has a back contact 49 and is connected to the backcontact 15. The back contact 89 is connected to the back contact iii ofthe change-down relay 8. The relay ll has a movable contact 50 connectedto the back contact 39 of relay 40 and is arranged to make with a fixedcontact 5! which is connected to an electro-magnet 52 for bringing inthe third speed. The movable contact 50 is also connected to a contact53 in the automatic selection switch. When the switch arm is in fourthspeed position, this contact 53 is connected by the contact strip El toa contact 5E which is itself connected to an electromagnet 55 forbringing in the fourth speed, this being effected, it will be noted,without the intervention of a relay.

The contact strip 25 of the ratchet switch controls a series of pairs ofcontacts ee, 57!; 5t, 59; and til, 69 which correspond to first, secondand fourth speeds respectively. The contacts E-ii, 58 and (it areconnected together and to an appropriate contact in the manual selectionswitch. The contacts 5? and 59 are connected through a resistance $2 tothe end I33 of change-up relay coil 4. The contact BI is connected tothe coil of the change-down rela 8. A fifth electro-magnet coil 63 isprovided for bringing in the reverse gear. All the electro-magnet coilsare connected on one side to the negative side of the battery 33. Theelectro-magnet coils it, d3, 52 and 5'5 are connected on the other sidethrough the m terconnected relay contacts and an economising resistance65 to the positive supply through appropriate contacts in the manualselection switch. The contacts 1 and E2 on the changeup and change-downrelays 4 and 8 are arranged to short-circuit the resistance 65 wheneither one of the relays is energised so that the current in theselected solenoid coil is a maximum at this time. As soon as the relayhas caused operation of the appropriate ratchet, the contacts 29 or ason the ratchet are broken so that the relay is de-energised after thepreviously mentioned time delay and the resistance 65 is re-introducedinto the selected electromagnet circuit, thereby diminishing the currentflowing.

It will be understood that the electro-inagnets previously referred toare arranged to operate hydraulic or pneumatic valves controllinghydraulic or pneumatic pistons for applying the brakes and/or clutchesto epicyclic gears and thereby engaging the corresponding gear ratio ofthe gear box. A convenient arrangement for this purpose is illustratedin Figure 2. A gear box indicated generally at 665 is of the usualepicyclic type and has a brake drum (not shown) with brake band t8 andline 61, one end of which is anchored by a link $9. The other end of thebrake band is connected to a link if! having a head "ll bearing on alever l2 fulcrumed at 13 on the link 69 and bearing at its other end ona bell crank is pivoted at and connected by a rod '66 to a pneumaticpiston "H. Air from a supply pipe i8 is admitted to the operatingcylinder is under the control of a spring loaded valve an connected by aspindle 8| to an armature 82 arranged to be actuated by theelectro-magnet coil 83 to open the valve 80. An exhaust outlet 8 iscontrolled by a valve member 85. An arrangement of this kind is employedfor bringing in the four forward speeds and the reverse gear.

The manually operable selection switch is shown in Figures 3 and i andthe contact arrangement is shown in Figure 1. The movable part of theswitch comprises four contact or brush arms 36, 3?, 88 and 89, two ofwhich are shown in Figure 3. These arms are in electrical connection andare arranged in the form of a cross upon a plate as which is supportedby means of a central recess s1 upon a central pivot 82 which isvertically movable against a loading spring 93. A handle 9G is locatedupon the plate 98 and is secured thereon by an upper plate at rotatablyseated in a central sleeve 96 in the switch casing 9'5 and connected tothe lower plate fit. Springs 98 are interposed between the upper plateand the handle body, and the latter is also connected by horizontalpivots 98a to side plates as of the upper plate 95. A pin mil in theupper plate $5 is engageable in any one of a series of indexing recessein a member is! secured to the casing 9?. The handle lid projectslaterally through an opening in the casing wall, which opening is ofgate form as shown in Figure i and comprises spaced parallel slots seeand 583 connected intermediately by a short vertical slot ta l. Theupper slot 102 has markings 3 and 4 indicating third and fourth speeds.Instead of 4 the marking A may be employed to indicate automaticcontrol. The lower slot its is marked R, 1 and 2 for reverse, first andsecond speeds. A spring loaded pin is mounted in the casing to preventinadvertent movement of the handle to reverse position. The arrangementis such that the handle at can be rocked about its pivot pins 98a forpassing through the gate slot Hi4 and can be moved laterally in eitherof the slots [02, I03 and indexed in the marked positions. A rod IDS isslidable longitudinally in the handle and is displaceable by a buttonit? in the handle end. The rod I35 engages a double conical orequivalent cam-shaped member Hi8 located in an enlarged bore in thehandle body and loaded by a spring ice. The member its is engaged by aball [it located in an aperture in the handle body wall, the ball beingengaged by a pin III engaging a second ball H2 located within the sleeve98. A screw M3 on the casing 9'! abuts the ball H2. This ball and pinarrangement is aligned with the spring loaded supporting pivot 92. Thearrangement is such that pressure on the handle button it? displaces thecone member liltand thereby forces the contact plate 99 downwardly bydepressing its supporting pivot s2. This motion also brings with it theupper plate 95 and releases the pin 59%] from the indexing recesses inthe member It'll, thus enabling the contact plate to be angularlyadjusted to another position. Four groups of contact studs are arrangedbeneath the contact arms, and two of these studs are shown at I M inFigure 3.

Referring to Figure 1, three contact studs H5, H8 and Ill comprise onegroup and are disposed at a level such that they will only be contactedby the arm 3? when the handle 94 is in the upper slot H325 of the gate,this being determined by the corresponding inclination of the contactarm plate lit. The stud H5 is a fourth Speed or automatic control studand is connected by a line IIS through the contacts 29 and 30 to thegovernor controlled contact member 1. The stud H6 is a neutral stud andis connected to the third speed stud Ill and thence by a line II9 to thepositive side of the third speed electro-magnet 52. A second group offour studs comprises a neutral stud I2I which is connected by a line I24to the contacts 55, 58 and 60 of the automatic selection switch whichare only contacted by the strip 26 when the arm is in first, second, orfourth speed positions. This neutral stud I2I is contacted by the arm 89when the neutral stud H5 is contacted by the arm 81. The studs I26], I22and I23 are all connected to the contact arms 5, 9 and IQ of thechange-up and change-down relays. This second group of contacts areengageable by the contact arm 89 in either the upper or lower slotposition of the handle 94. A third group of contacts comprises fourstuds I25, I26, I27 and I28 all connected to the positive side of thesupply battery 33 and the economising resistance 65. These studs arearranged so that they are only engaged by their contact arm 88 when thebutton IIJ'I of the handle is depressed as is necessary when changingthe handle position, and when contacted they short-circuit theresistance 65 when the circuit of the selected electro-magnet is closed,the resistance being re-introduced when the button is released. A fourthgroup of contacts comprises contact studs I29, IEG, I3I and I32 whichare arranged so that they are only engaged when the handle at occupiesthe lower slot. The end or reverse stud 213 is connected to the positiveside of the reverse gear electro-magnet 63. The first speed stud IE3 isconnected to the positive side of the first gear electro-magnet 4G. Theneutral stud I3I is connected to the end stud I32 and to the positiveside of the second speed solenoid 4B. Thus when the arm 86 contacts withthe appropriate stud of the fourth contact group, the circuit of eitherthe reverse, first or second speed electromagnet will be completedthrough the corresponding stud of the second group (I20, I22 or I23)which is connected through the resistance 65 to the positive side of thebattery 33. The arrangement is such that when the switch handle 94 ismoved to fourth speed or automatic control position, automatic controlis afforded from first to fourth speeds. Movement of the switch handleto reverse, first, second or third speed positions interrupts theautomatic control circuits and closes the electro-magnet circuit of theselected gear to engage the same, the economising resistance 65 beingshort-circuited by contacting of the studs I25, I25, I27 or I28 as longas the handle button IE2? is depressed. Also the contacts of the groupsare so arranged that a neutral contact is made when moving the handlethrough the gate from any one of the positions 1, 2, 3 or 4 (A) to anyother of said positions.

It will be seen that with the manual selection switch in neutralposition there is no electrical connection to the contact I I5 which isconnected to the governor member I, nor is there any electricalconnection to contacts I39, I32, II? or I29 because the arm 38 does notmake with any of the supply contacts I25, I25, I2? or I23 unless thebutton of the switch handle is depressed, and the contact arm 89 lies ona contact I2I which is not connected to the supply. Thus none of theelectro-magnets is energised and no gear is engaged,

It is not possible to move the switch arm 94 without first pressing thebutton I01, and this action causes the arm 88 to engage contact groupI25, I26, I27, I28. Thus when the switch arm is moved to any one of thepositions R, 1, 2 or 3, the four contact arms are electrically connectedto the positive side of the battery and the arm 86 or 87 will carry theconnection to the appropriate contact and current fiows directly to theappropriate electro-magnet winding, the circuit of which is completedthrough the common connection to the negative side of the bat tery. Whenthe button I6? is released in the selected gear position the directconnection with the battery is interrupted by disengagement of the arm88 with its group of contacts, but a reduced current is maintainedthrough the arm 89 which is then engaged with one of the contacts I26,I22 or I23 which are connected through the economising resistance to thepositive side of the battery. Thus having first applied the full batteryvoltage to the appropriate electro-magnet to ensure its positiveactuation, a reduced current is then maintained to hold the magnet in itactuated position. This enables a relatively small magnet to be usedwithout overheating when energised for long periods.

It is desirable that during manual control of the gear box as describedabove, the ratchet switch for automatic selection should be in thirdgear position, order that when it is brought into eiiect by reverting toautomatic control it will not immediately actuate a gear ratio whichmight be too low or too high for the speed of the vehicle at the time ofgear change. If the ratchet switch should be in first or second speedposition when the automatic control is discontinued by moving the manualselection switch to a selected position the switch arm will of necessitybe moved through the neutral position with the button I Eil depressed.This will complete a connection from the positive side of the batterythrough contact I27, arm 88, arm 39, contact I2I, and contact strip 26on ratchet switch arm to the end 53a 01' the winding of the change-uprelay, and thence through contact strip 24 of the ratchet switch andcontacts 32 to the negative side of the battery. The changeup relay 4 isthus energised to complete a circuit from the positive side of thebattery through relay contacts '5, contact arm 5 and contact 6 to magnetwinding I5 and thence to the negative side of the battery. The magnet i5is thus energised and moves the ratchet switch one step in a change-updirection, for example from first speed to second speed position. Thenext operation of the manual selection switch through the neutralposition will repeat the energising of the change-up relay t and movethe ratchet switch to third speed position. Further movement of themanual selection switch can have no effect upon the change up relaysince the contact strip 25 on the switch arm will not make the necessarycontact.

If the ratchet switch had been in fourth speed position when automaticcontrol was discontinued, the ensuing movements of the manual switch arm94 would complete a circuit through the ratchet switch contact strip 25and contact SI to the end I 34 of the change-down relay coil 8, andthence through the coil to contact 34, through contact strip 24 tocontacts 32, and thence to the negative side of the battery. Op-

eration of the change-down relay 8 which ensues will complete a circuitfrom the positive side of the battery through relay contacts H and i2and contact arm 9 to the magnet winding it and thence to the negativeside of the battery. The operation of the magnet is will then move theratchet switch one step to third speed position.

Considering now the functioning or the automatic control, let it beassumed that the ratchet switch is in third speed position when themanual selection switch is moved to position 4 or A. This completes acircuit from the positive side of the battery through contact I28, armtil, contact M5, line H8, line I55, ratchet contact strip 2%, contact38, relay winding M and thence to the negative side of the battery. Therelay is thereby energised to complete a secondary circuit from thepositive side of the battery through contact lZB, arm 88, arm 89,contact 28, line ltd, contact arm it, contact it (or alternatively linel3l, contacts 42, 45, G6, 49), contacts to and H of third speed magnetrelay and through magnets 52 to the negative side of the battery,thereby engaging the third speed. When the button Hill is released bythe operator, the circuit from the battery is completed through theresistance 55 as previously explained. If the vehicle is stationary whenthe automatic control is selected, or if for any other reason the enginespeed is low enough to close the change-down contacts l, 3 in thegovernor switch, current will now from the positive side of the batteryto the resistance 55 (the handle button till being assumed released) tocontact I203, arm 89, arm contact 5525, contacts 3i] and 29, governorcontact arm l, governor contact 3, the change-down relay coil 8,contacts 34, contact strip 24, contacts 32, and thence to the negativeside of the battery. The changedown relay 3 is thereby energised and thecondenser 35 is charged, the relay in turn closing and completing acircuit from the positive side of the battery through the relay contact52, contact arm a, contact H, magnet coil is and thence to the batterynegative, thereby operating the ratchet switch to move its arm one stepdown to I second speed position, thereby transferring the circuit fromthe third speed relay winding ll to the second speed relay winding as.The contacts of the second speed relay to will thereby be closed tocomplete a circuit from the positive side of the P battery through thechange-down relay contact l2 and contact arm 9, line ltd, line 93?,relay contacts 42 and 35, relay contacts it and ll, the second speedmagnet winding (it and thence to the negative side of the battery. Whenthe contacts db and 5'? are closed, the contacts tit and 59 are opened.Simultaneously with the closing of the change-down relay contacts 82, Hand 9, the back contacts is and is are opened, thereby interrupting thecircuit of the third speed magnet relay contacts 5d and 5E, so thatwhile the induction sleeve provided on the winding of the third speedrela winding il retains its contacts til, Si in closed condition for therequired period for a changing-up operation (about second), the circuitsupplying these contacts is instantaneously broken by the aforesaid backcontacts it, it of the change-down relay, and the lag which is inherentin the action of the relay is prevented from being effective in thethird speed magnet winding 52 which it has been controlling. Theoperation of the ratchet switch causing the change-down operation totake place has previously opened the contacts as and interrupted thecircuit to the governor switch contacts i and 3 and the changedown relaycoil 8 and its condenser so that the latter commence to dischargethrough its relay coil and holds the relay closed for a predeterminedperiod (about two seconds). When this relay opens the circuit to thechange-down magnet 353, the ratchet contacts 3d will be closed and thegovernor switch member i will again be connected to the positive sideor" the battery and is ready for a further operation should the enginespeed and throttle position be such as to close its contacts. A manualswitch its is provided and connected to the contact 53% which is similarto contacts but occupies the second speed position of the ratchet switchcontact strip When the manual switch is opened, the circuit through thechange-down relay 8 will be broken when the ratchet switch arm reachesthe second speed position and a further change-down cannot then occur.

If the engine speed rises sufliciently to close the governor switchcontacts and 2, a circuit is completed from the positive side of thebattery through the economising resistance the contact 52d of the manualselection switch, the switch arms as and ill, the contact H5, contactsiii and governor switch arm i, governor switch contact 2, the change-uprelay winding t and its condenser 85, the contacts it, the ratchet armcontact strip 25., the contacts 32 and thence to the negative side ofthe battery. The consequent operation of the change-up relay closes acircuit from. the positive side or" the battery through the change-uprelay contacts 1, ii and 6 through the magnet coil E5 to the negativeside of the battery. The ratchet switch is thereby moved up one step,for example from second to third position. The movement of the ratchetarm contact strip transfers the supply from the relay coil at to therelay coil ll. The relay contacts l-5, fill remain closed for about halfa second, maintaining the circuit through the second speed magnet 48 forthis period after the actuation of the third speed magnet 52. It is tobe noted that the circuit which supplies the relay contacts 56, 5| isnot interrupted when changing-up as it is when changing-down. Theoperation of the ratchet switch when changing-up opens the contacts 294and thereby interrupts the circuit to the governor switch arm l andthence through the contact 2 and the change-up relay l and its condenser35. The condenser then commences to discharge through the relay windingit and maintains the relay contacts closed for approximately twoseconds. During this period the aforesaid contacts 29 remain open andrender the governor switch inoperative. This provides sufiicient timefor the engine speed to accommodate itself to the new gear ratio beforethe governor switch becomes operative again. When the next upward changeto fourth speed takes place, the ratchet switch contact strip 25interrupts the circuit of the third speed relay coil All and the ratchetswitch contact strip 27! occupies a position bridging the contacts 53and 5t, thereby closing a circuit from the positive side of the batterythrough the change-up relay contacts l and 5, the line 36, the backcontacts is and Hi of the change-down relay, the contacts 53 and a lpreviously men tioned, the fourth speed magnet 55, and thence to thebattery negative. In the fourth speed position of the ratchet switch thecontact strip 24 interrupts the circuit of the change-up relay windingfl and no further change in the upward direction of the switch can takeplace.

It is to be noted that the main purpose of the magnet relays 39, 44, 4!is to provide a slight pping of the magnet operations when changing-upas distinct from changing-down. For this reason the fourth speed magnetis not provided with a relay since no higher speed is provided. If therelays are needed to relieve the ratchet switch of heavy current, then asimple relay without an induction sleeve could be provided for thefourth speed magnet, its contacts replacing the existing contacts 55, 54of the ratchet switch and its winding being connected between theratchet switch arm contact corresponding to contact 38 but in fourthspeed position, and the battery negative.

It will be seen that the back contacts 45 and 49 of the first and secondspeed magnet relays are employed to provide a supply circuit from theline 53f through each relay to the next higher speed relay so that whenchanging-down, the incoming relay isolates the next higher speed relayso as to prevent its lag factor from being effective when changing-down.When changingup, however, the incoming relay has an independent supplyprovided by the back contacts I3 and I4 on the change-down relay, as theoutgoing relay remains closed for about half a second and is thereforeunable immediately to supply the next higher speed relay through itsback contacts.

The contact members I, 2 and 3 which are moved in accordance with speedand fuel or throttle conditions to effect automatic gear changing may bearranged as described in British patent specification No. 457,269, butpreferably the construction shown in Figures 5, 6 and 7 is employed.This comprises a casing I45 in which is rotatably supported a shaft I4Icarrying a pulley I42 which is driven from the engine. The governoractuated member I43 is of generally V shape carrying a V-shaped spring44 on which are mounted a pair of contact studs I45, and is mounted on aspindle I46 for angular motion. A second rotatable spindle I41 carries apair of contoured contact plates I48 secured to an insulating base I 49and arranged between the aforesaid contact studs I45 which are inelectrical connection. The spindle I4! has an arm I 55 which can beactuated from the throttle control of the internal combustion primemover, the arrangement being such that at different angular positions ofthe spindle I41, the contact surfaces of the contoured plates I48 are atdifferent distances from the contact studs I45. The speed governor is ofthe centrifugal type and comprises the shaft Mi mounted in bearings II.Two centrifugal weights I52 are connected by duplicate links I53 to across pin I54 extending through the shaft, the weights being shaped asrollers which lie one on each side of the shaft with their axes at rightangles to the shaft axis. A collar I55 slidable on the shaft I4I carriestwo bearing members I55 which extend outwardly between the links I53 andare formed with bearing surfaces I5? preferably perpendicular to theshaft axis upon which the weights I52 can roll. The sliding collar !55is loaded by a spring I58 which abuts against a second collar I59 fixedto the shaft. A cross pin I65 on the sliding collar I55 extends througha longitudinal slot in the shaft communicating with a bore I6I extendingto one end thereof. Slidable longitudinally in the bore IBI is a rodI52, one end of which engages the cross pin I55 and the other end ofwhich protrudes from the shaft and engages an arm I63 on the spindle I46 through a thrust ball I64. The arrangement is such that at apredetermined speed of the shaft I4! the centrifugal weights I52 moveoutwards by rolling along the bearing surfaces I5! and thereby displacethe sliding collar l55 against its spring loading. This move mentdisplaces the rod I62 and moves the arm I53 of the V contact member I43to bring one of the contact studs I45 into engagement with the adjacentcontoured contact plate I48 and thereby operate the relay means foreffecting a change to a higher gear ratio. When the speed falls to asufficient extent the sliding collar I55 returns, permitting the Vmember I43 to move in the opposite direction under the action of asuitable return spring I53a so that contact is made with the othercontoured plate and thereby causes a gear changing operation to a lowerratio. It will be understood that the two contact plates I48 correspondto the plates 2 and 3 of Figure 1, and the V contact spring I 44 andstuds I45 correspond to the contact arm I of said figure.

A modified form of control circuit, which may be employed in place ofthe circuit of Figure 1 when desired, is shown in Figure 8. The modifiedcircuit is generally the same as that previously described, but themagnet relays and for the first and second speed magnets 44 and 48 haveno back contacts. In place of these, the ratchet switch arm has acontact strip I55 which makes contact with a continuous fixed contactI65 connected to the change-down relay contact I204, and with fixedcontacts I81, I68 which occupy the second and third speed positions ofthe arm respectively and are connected directly to the second and thirdspeed magnets 48 and 52, thereby providing a direct supply for thelatter. The supply to the contacts and of these second and third speedmagnet relays during a changing-down operation is interrupted by theback contact I 59 on the change-down relay 8. Also during suchoperation, a supply is provided to the ratchet switch contact strip Ithrough the contacts 9 and I2a on the change-down relay. Thus owing tothe fact that the valve actuating magnets 48 and 52 are directlyenergised without the intervention of their respective relays whenchanging from a higher to a lower gear, there will be no lag oroverlapping of these operations. The relay coils are provided withinduction sleeves as in the previous example which afford a lag of abouthalf a second in the operation of the relays, and this is effective whenchanging from a lower to a higher gear since the magnets are energisedthrough the operation of their respective relays, and hence the desiredoperational overlapping is obtained.

The modified circuit also has no economising resistance 65 as in thearrangement of Figure 1, and hence additional short-circuiting contactson the change-up and change-down relays are not required, therebysimplifying the circuit.

t will be seen that when using control means as described above with theselection switch set for automatic operation, an increase in enginespeed to a predetermined value causes closing of the governor actuatedswitch and operation of the automatic selection switch to engage thenext higher gear. The introduction of the higher gear reduces the speedof the engine temporarily and causes the governor actuated contacts toopen. Converse operations take place when the engine speed falls and thegear ratios are progressively changed-down. If the arrangement is fittedto a vehicle having an automatic clutch or fluid flywheel, the vehiclemay be brought to rest by applying the road wheel brakes and the enginecan continue to operate at idling speed although the low gear isengaged.

The invention provides a convenient and eifective means enabling manualcontrol of the gear changing operations to be substituted for automaticcontrol when desired, as for example for the purpose of maintaining alow gear in engagement when the vehicle is descending a hill. Theinvention is not restricted to the example described, since differentnumbers of gears may be arranged to be controlled by both automatic andmanual means. Also the actuation of the gear engaging means may beeffected in various ways, for example directly by electro-magneticmeans. Further, the invention is not restricted to automatic controldependent upon speed and fuel sup ply or throttle conditions. Thusinstead of the governor actuated switch, a pair of push button switchesmay be provided for example, one controlling a change-up change-downrelay or equivalent means, the remainder of the control arrangementsbeing similar to those previously describe What I claim is:

1. Change speed gearing having electrical control means comprising, incombination, two first circuits controlled by contact making members,means adapted to be controlled by a speed sensitive device driven fromthe input side of the speed gearing for actuating said contact makingmembers to control said circuits alternatively, stepwise actuatablemeans controlled by one of said first circuits for efiecting engagementof a next higher gear when actuated and controlled by the other of saidfirst circuits for effecting engagement of a next lower gear whenactuated, a manually operable selection switch means controlling saidfirst circuits and having rality of positions, further circuitscontrolled by said selection switch means, and electrical means forcontrolling engagement of different gear ratios in said furthercircuits, whereby gear changing is efiected either automatically or bymanual selection according to the position of said selection switchmeans.

2. Change speed gearing according to claim 1, in which the contactmaking members comprise two elements movable relatively in twononparallel directions, movement in one direction being controlled bythe speed sensitive device, and movement in the other direction beingcontrolled by means responsive to the regulation of the fuel supply tothe prime mover.

3. Change speed gearing according to claim 1,

in which the stepwise actuatable means are arranged to actuate a switchmechanism alternatively in opposite directions for controlling difierentcircuits for cheating engagement of different gear ratios.

4. Change speed gearing according to claim 1, comprising relays in saidfirst circuits, and a selection switch operable alternatively inopposite directions the stepwise actuatable means to close circuits foractuating the different gear ratio engagement means.

5. Change speed gearing according to 1, comprising relays in said firstcircuits, a selection switch operable alternatively in oppositeclirections by the stepwise actuatable means to close circuits foractuating the different gear ratio engagemnt means, and time relay meanssuch as shunt connected condensers combined with the relays to preventsuccessive operation thereof within a predetermined period.

relay and the other a 6. Change speed gearing according to claim 1,comprising electro-magnetic devices for controlling engagement of theselected gear.

7. Change speed gearing according to claim 1, comprisingelectro-magnetic devices for controlling engagement of the selectedgears, and electrical relays controlling at least some of said devices.

8. Change speed gearing according to claim 1, comprisingelectro-magnetic devices for controlling engagement of the selectedgears, electrical relays controlling at least some of said devices, andtime delay means combined with said relays.

9. Change speed gearing according to claim 1, comprisingelectro-magnetic devices for controlling engagement of the selectedgears, electrical relays controlling at least some of said devices, timedelay means combined with said relays, and means for preventing saidtime delay means from being effective when changing from a higher to alower gear.

10. Change speed gearing according to claim 1, comprisingelectro-magnetic devices for controlling engagement of the selectedgears, electrical relays controlling at least some of said devices, timedelay means combined with said relays, and contacts actuated by one ofsaid relays in a circuit for isolating another relay corresponding tothe next higher speed gear when the first said relay is energised,whereby the time delay of said second relay is rendered ineffective andthere will be no overlappin of the difierent gear engagement periodswhen changing from a higher to a lower gear.

11. Change speed gearing according to claim 1, comprisingelectro-magnetic devices for controlling engagement of the selectedgears, electrical relays controlling at least some of said devices, timedelay means combined with said relays, an automatic selection switchoperated by the stepwise actuatable means, relay means controlling saidselection switch, and contacts actuated by said relay means forinterrupting the supply of current to the relays controlling the saidelectromagnetic devices.

12. Change speed gearing according to claim 1, in which the manuallyoperable switch means has contact means automatically engageable eachtime the switch is operated to change the gear ratio, and a circuitclosable by said contact means is associated with an automatic selectionswitch whereby the positioning of said selection switch in anintermediate position is ensured and thereby inappropriate gear changesare obviated.

13. Change speed gearing according to claim 1, comprising a plurality ofgear engaging electrical control devices, a current economisingresistance in the circuits of said devices, and means actuated. inresponse to each gear changing operation for short-circuiting saidresistance.

14. Change speed gearing according to claim 1, comprising a plurality ofgear engaging electrical control devices, a curr nt economisingresistance in the circuit of said devices, means for locking the operaing handle of the manually operable selection switch means in eachselected position, means actuated by unlockin motion of the handle forclosing contact means, and circuit means including said contact meansfor shortcircuiting resistance when the handle is moved from oneposition to another.

15. Change speed gearing according to claim 1, comprising a plurality ofgear engaging electrical control devices, a current economisingresistance in the circuit of said devices, an operating handle for themanually operable selection switch means for the manually operableselection switch means arranged for guided movement in a slot of gateform, contact arms associated with the handle and rotatable thereby,means for locking said handle in each selected position, a spring loadedbutton in said handle for releasing the locking means, means actuated byunlocking motion of the handle for closing contact means, and circuitmeans including said contact means for shortcircuiting said resistancewhen the handle is moved from one position to another.

17. Change speed gearing according to claim 1, comprising a plurality ofgear engaging electrical control devices, a current economisingresistance in the circuit of said devices, an operating handle for themanually operable selection switch means arranged for guided movement ina slot of gate form, depressible contact arms associated with the handleand rotatable thereby, means for looking said handle in each selectedposition, a spring loaded button in said handle for releasing thelocking means and arranged to depress said contact arms when the buttonis operated, and contacts adapted to be made by depression of said armsfor short-circuiting the resistance, the latter being re-introduced whenthe button is released.

l8. Change speed gearing according to claim 1, in which the contactmaking members are movable relatively in two directions, movement in onedirection being controlled by the speed sensitive device, and movementin another direction being controlled by means responsive to theregulation fuel supply of the prime mover, one of said memberscomprising a pair of electrically connected contacts mounted in spacedrelation for angular movement in unison, and the other of said memberscomprising a pair of contoured contact plates mounted for angularmovement and arranged so that the spaced contacts will make contact withone or other of the plates when relative movement takes place.

19. Change speed gearing according to claim 1, in which the contactmaking members are movable relatively in two directions, movement in onedirection being controlled by the speed sensitive device, and movementin another direction being controlled by means responsive to theregulation of the fuel supply of the prime mover, said contactscomprising a pair of spaced and electrically connected contacts mountedon a V-shaped member for angular movement in unison, said V- shapedmember being operable from the speed governor, and a pair of contouredcontact plates mounted for angular movement and arranged so that thespaced contacts will make contact with one or other of the plates whenrelative movement takes place.

20. Change speed gearing according to claim 1, comprising a speedsensitive device having arms carryin centrifugal weights which haverolling engagement with a bearing surface on or associated with a membermovable along the axis of weight rotation against resilient loading, thesaid bearing surface being transverse to said axis so that thedisplacement of the member is approximately proportional to the changein speed.

21. Change speed gearing according to claim 1, in which the stepwiseactuatable means comprise oppositely acting ratchet means combined witha ratchet wheel operating a selection switch.

ALBERT ARTHUR MILLER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,100,748 Prince Nov. 30, 1937 2,251,625 Hale Aug. 5, 19412,433,099 De Normanville Dec. 23, 1947 2,540,639 Winther et a1 Feb. 6,1951

